This invention relates to a gas insulated switchgear.
FIG. 1 is a side view of one example of a conventional three-phase-in-one type gas insulated switchgear disclosed in Japanese Patent Laid-Open No. 60-213213 for example, and FIG. 2 is a plan view of FIG. 1. FIG. 3 is a single line connection diagram of the switchgear shown in FIGS. 1 and 2.
As shown, the conventional switchgear establishes an electrical connection from the main bus bars 2 through a bus bar disconnector 3, an interrupter vessel 1 (on the bus bar side), and a line disconnector 4 (on the line side), to cable heads 5 and 6 respectively disposed in two separate cable head vessels. The first cable head vessel includes first and second lead-in terminal portions 20 and 21 and the second cable head vessel includes a first lead-in terminal portion 22. On the bus bar side of the interrupter vessel 1, which houses interrupters operable to interrupt currents flowing therethrough, there is provided with a first lead-in terminal portion connecting the vessel with the bus bar disconnector 3. On the line side of the interrupter vessel 1 a second lead-in terminal portion 19 is connected to vessel 9 of the first cable head vessel through the first lead-in terminal portion 20 of the first cable head vessel and bellows 13. Within the first cable head vessel, the line disconnectors 4 and the first cable heads 5 are enclosed.
Further, a second lead-in terminal portion 21 of the first cable head vessel is connected to the second cable head vessel 10 through its first lead-in terminal portion 22.
The reference numeral 7 indicates conductors connecting the components, 8 insulating spacers, 11 first cables extending from the first cable heads 5, 12 second cables extending from the second cable heads 6, 14 an operating mechanism for operating the interrupter within the interrupter vessel 1, 15 and 16 first and second cable current transformers, and 17 grounded switches.
Since the conventional three-phase-in-one type gas insulated switchgear is constructed as above described, the conductors 7 for connecting the first lead-in terminal portion 22 of the second cable head vessel 10 to the second cable heads 6 must be significantly long, and the second cable head vessel 10 must be significantly high, resulting in disadvantages in the space usage and economy.